Explosion-proof starter



Oct. 26, 1948. w. F. EGKERTv I EXPLOSION-PROOF STARTER Filed April 12, 1945 Patented ct. 26, 1948 UNITED STATES PATENT OFFICE 8 Claims. 1

This invention relates to a new and improved explosion-proof starter for the engines of motor vehicles, especially designed and adapted for use on trucks and other motor vehicles, such as have been used for the transportation of gasoline and munitions in landing operations in the present war, the invention I have being `adapted for use generally wherever the safety features incorporated in accordance therewith are important or desirable.

The principal object of my invention is to provide any explosion-proof starter assembly in which an air-tight housing, which tightly encloses the housing of the starter motor, has an annular internal shoulder in one end thereof abutting the adjacent end of the motor housing remote from the motor brush assembly end, so

vthat if an explosive mixture finds its Way into lthe brush space and is ignited by sparks from the brushes of the motor in the starting of the engine, the pressure in that end of the air-tight housing tends to move said housing in a, direction to bring the aforesaid internal annular shoulder into tighter contact with the adjacent 'end of the motor housing, so that there cannot be any sudden discharge oi hot gases and, consequently, the danger of any serious-explosion is averted, the seepage of the gases past the annular internal shoulder being too slow to give rise to any danger of igniting anything of a highly `volatile or explosive character that may happen to be in the vicinity.

The invention is illustrated in the accompanying drawing, in which- Fig. 1 is a side viewof an explosion-proof l starter assembly made in accordance withv my invention, showing a portion of the air-tight housing in section, to better illustrate the annular internal shoulder provided thereon for abutment with the adjacent end of the starter motor housing, and

Figs, 2 and 3 are end views of the assembly from opposite ends thereof.

The same reference numerals are applied to corresponding parts throughout these views.

y The engine starter motor 4 has the usual brush assembly 5 on one end thereof, and at the other end has the usual Bendix gear 6 on the threaded portion 1 of the armature shaft 8. The Bendix gear 6 Works inside the extension 3 of the end yportion I0 of the motor housing, on which the usual ears II are provided for bolting the motor onto the flywheel housing of an internal combustion engine.

In accordance With my invention, an air-tight housing, indicated generally by the reference numeral I2, is provided enclosing the starter motor with a fairly tight t at I3 annularly of the middle substantially cylindrical portion of the yhousing of the motor, so that in the event an explosive mixture iinds its way into the end I4, Where it may be ignited by sparks from the brushes of the motor in the starting of the engine, the pressure thus created tends to move the housing I2 in the direction away from the Bendix gear 5 so as to bring the annular internal shoulder I5 in the housing I2 into tighter contact with the annular shoulder IS provided on the adjacent end of the housing of the motor 4. In that way there can be no sudden discharge of hot gases, because the only escape for the gases under pressure from the space I4 is through the restricted passage I3 in the air-tight housing I2 substantially the full length of the motor housing and thence through the joint lE-l 6 between the abutting ends of the air-tight housing and motor housing, and, of course, such seepage is entirely too slow to give rise to any danger of causing an explosion should there be anything in the vicinity of the starter motor of a highly volatile or eX- plosive character. While the air-tight housing I2 may be of any suitable or preferred construction, I have disclosed one made of three parts, namely, a cap Il, which is annularly anged, as indicated at I8, and a generally cylindrical main body made in two parts, I9 and 2G, these parts having longitudinally extending flanges 2 I, which are arranged to be bolted together, as indicated at 22, and annular end anges 23 which are arranged to be bolted to the annular flange I8 on the cap II, as indicated at 24. All of these flanges t together closely enough to insure good seals when thev bolts are tightened and thus avoid any likelihood of leakage of hot gases directly from the air-tight housing I2 in the event an explosive mixture is ignited within the housing. Fittings 25 are entered in holes 26 in the hollow boss portion 21 provided on the housing part I9 for the extension therethrough of the necessary leads to the starter motor, these leads being surrounded by hose connections 28 with suitable packing, so that there will be no danger of leakage of hot gases from the air-tight housing I2 at these points in the event an explosive mixture is ignited inside said housing.

It is believed the foregoing description conveys a good understanding of the objects and advantages of my invention. The appended claims have been drawn to cover all legitimate modifications and adaptations.

claim:

1. In combination with an electrical machine having a generally cylindrical housing and having a brush assembly in one end and an armature shaft extend-ing from the other end, means on the latter end portion of the housing for mounting the housing on a support, an air-tight explosion resisting housing for enclosing' the housing of said ,machine from the brush assembly end to the other end, said enclosing housing being generally cup-shaped md having a tight friction t on the cylindrical exterior of said machine housing, whereby said enclosing housing is supported on said machine housing and an explosion occurring in the inner end of the enclosing housing will cause endwise displacement of said enclosing housing toward the brush assembly end, said enclosing housing having an annular internal shoulder in the open end thereof for abutment annularly on the adjacent end of the machine housing with an air-tight t to limit such endwise displacement.

2. A structure as set forth in claim 1, wherein said enclosing housing is of sectional construction and vcomprises a cup-shaped cap section for removably enclosing the brush assembly end of the machine housing, and a main body section for enclosing the rest of the machine housing, said main body section having the annular internal shoulder in the end remote from the cap section, said cap section being detachable from the other end of said main body section.

3. In combination with an electrical machine having a generally cylindrical housing and having a brush assembly in one end and an armature shaft extending from the other end, an air-tight explosion resisting housing for enclosing the housing of said machine from .the brush assembly end to the other end, said enclosing housing being generally cup-shaped and having a tight friction nt on the cylindrical exterior of said machine housing, whereby an explosion occurring in the inner end of the enclosing housing will cause endwise displacement of said enclosing housing toward the brush assembly end, said enclosing housing having an annular internal shoulder in the open end thereof for abutment annularly on the adjacent end of the machine housing with an air-tight fit to limit such endwise displacement, said enclosing housing being of sectional construction and comprising a cup-shaped cap vsection for removably enclosing the brush assembly end of the machine housing, said cap having an annular flange thereon, and two semi-circular sections for enclosing and frictionally clamping therebetween the rest of the machine housing, the latter sections having longitudinally extending anges which are arranged to be bolted in abutting air-tight relation clamping the machine housing between said sections, and an annular flange on one end arranged to be bolted in abutting air-tight relation to the annular iiange on said cap, said sections having the annular internal shoulder in the other end thereof.

4. An explosion-proof starter motor for an internal combustion engine comprising, in combination with a generally cylindrical motor housing having a brush assembly in one end and having a reduced extension on the other end surrounding a Bendix gear mechanism and the projecting end of the motor armature shaft, means on said reduced extension for mounting said housing on a support, an air-tight explosion resisting housing for enclosing the housing of said motor from the brush assembly end to the other end, said enclosing housing being generally cup-shaped and having a tight friction fit on the cylindrical exterior of said motor housing, whereby said enclosing housing is supported on said motor housing and an explosion occurring in the inner end of the enclosing housing will cause endwise displacement of said enclosing housing toward the brush assembly end, said enclosing housing having an annular internal shoulder in the open end thereof for abutment annularly on the adjacent end of the motor housing with an air-tight fit to limit such endwise displacement.

5, A structure as set forth in claim 4, wherein said enclosing housing is of sectional construction and comprises a cup-shaped cap section for removably enclosing ,the brush assembly end of the motor housing, and a main body section for enclosing the rest of the motor housing, said main body section having the annular internal shoulder in the end remote from the cap section, said cap section being detachable from the other end of said main body section.

6. An explosion-proof starter motor for an internal combustion engine comprising, in combination with a generally cylindrical motor housing having a brush assembly in one end and having a reduced extension on the other end surrounding a Bendix gear mechanism and the projecting end of the motor armature shaft, an air-tight eXplosion resisting housing for enclosing the housing of said motor from the brush assembly end to the other end, said enclosing housing being generally cup-shaped and having a tight friction fit on the cylindrical exterior of said motor housing,

whereby an explosion occurring in the inner end` of the enclosing housing will cause endwise displacement of said enclosing housing toward the brush assembly end, said enclosing housing having an annular internal shoulder in the open end thereof for abutment annularly on the adjacent end of the motor housing with an air-tight nt to limit such endwise displacement, said enclosing housing being of sectional construction and comprising a cup-shaped cap section for removably enclosing the brush assembly end of the motor housing, said cap having an annular flange thereon, and two semi-circular sections for enclosing and frictionally clamping therebetween the rest of the motor housing, the latter sections having longitudinally extending flanges which are arranged to be bolted in abutting air-tight relation clamping the motor housing between said sections, and an annular flange on one end arranged to be bolted in abutting air-tight relation to the annular flange on said cap, said sections having the annular internal shoulder in the other end thereof.

'1. A structure as set forth in claim 1, wherein said enclosing housing is .of sectional construction and comprises a main body section for enclosing the main portion of the machine housing, and an end cover section for removably enclosing the brush assembly end of the machine housing, the main body section having the annular internal shoulder in one endl thereof remote from the cover section, said cover section being detachable from the other end of said main body section.

8. A structure as set forth in claim 4, wherein said enclosing housing is of sectional construction and comprises a main body section for enclosing the main portion of the motor housing, and an end cover section for removably enclosing the brush assembly end of the motor housing, the main body section having Ythe annular `internal 5 6 shoolder in one end theeof romote from the cover UNITED STATES PATENTS sectlon, sald cover sectlon bemg detachable from the other end of said main body section. Number Name Date WILLIAM F, ECKEHL 489,302 Goolden Jan. 3, 1893 5 1 .622,166 Shultz Mar. 22, 1927 REFERENCES CITED 1,990,279 Schaer-Glossl Feb. 5, 1935 The following references are of record in the le of this patent: 

